17 



destroyed, cau only be asked for with a backing of as much carefully 

 gathered scientific evidence as can be obtained, and it is the p.nrt of 

 preventive medicine and the experimental method to furnish some of 

 this evidence. 



Through the liberality and broad-mindedness of an association of 

 gentlemen in Boston, it is possible to present the results of certain 

 experiments undertaken to determine the question which is expressed 

 in the title of this paper. " How far may a cow be tuberculous 

 before her milk becomes dangerous as an article of food?" is an 

 extremely important point to decide. If it be considered already 

 settled and Koch's dictum be accepted, that there.is no danger in the 

 milk, if the mammary glands lie not affected, then there remains only 

 for the veterinary surgeon to determine the existence of such lesions, 

 and restrictive measures can go no further. If, however, the milk 

 from cows with no visible lesion of the lacteal tract be shown to con- 

 tain the specific virus of the disease in a not inconsiderable number 

 of cases, and if this milk be shown to possess the power of producing 

 the tuberculous process upon inoculation in small quantities and in 

 feeding experiments carried out with every possible precaution, then 

 restrictive measuies must have a far wider scope, and be carried on 

 from an entirely dift'ereut standpoint than has heretofore been con- 

 sidered necessary. 



It is familiar to most of us that little importance has been attached 

 to this question — the danger of milk from tuberculous cows with no 

 lesions of the udder — for the reason that many experiments have been 

 made with negative results, and because a priori reasoning would 

 seem to indicate the absence of such danger ; because tuberculosis is 

 not a disease like anthrax, in which the specific poison is to be found 

 in all parts of the system and is carried from one place to another by 

 the blood-stream. Koch's assertion that the milk from cows affected 

 with tuberculosis is dangerous only when the udder is involved, 

 appears to be based upon theoretical considerations rather than prac- 

 tical work in this especial direction. It has been widely accepted, 

 however, and the weight of his name has caused the assertion to be 

 repeated many times with but few attempts to verify its correctness. 



The increased attention that has been paid to the disease among 

 cattle, and the suspicions that have been aroused that tuberculosis 

 among the domestic animals is a more frequent cause of its appear- 

 ance among men than has been supposed, have made a caivful inves- 

 tigation of this point imperatively necessary. With the exception of 

 a few successful experiments by BoWmgev^Deutsch. Zeit. f. Thiermed., 



